Roofing Calculator
Calculate roofing squares and materials needed.
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How It Works
Calculates roofing squares (100 sq ft each) adding waste percentage. One square = 3 bundles of standard shingles.
Formula
Roof area with pitch factorQuick Reference
Common calculations — results you can verify instantly.
20×30ft roof footprint
20×30/100
6 squares (flat)
+20% for 6/12 pitch
6 squares × 1.20
7.2 squares
Shingle bundles
7.2 squares × 3
~22 bundles
Tips & Shortcuts
Add 10-15% waste for typical roofs. Complex roofs 20%.
Steep pitch dramatically increases material vs flat area.
Common Mistakes
Using floor area without pitch adjustment
Pitched roofs have more surface area than floor footprint.
Not adding waste for cuts
Ridges, hips, and valleys require cut shingles. Add 10-20% waste.
Frequently Asked Questions
Three bundles of standard shingles per 100 sq ft square.
3-tab: 15-20 years. Architectural: 25-30 years. Premium: 30-50 years.
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